This invention relates to the art of work supporting stands and, more particularly, to improvements in a foldable and transportable tripod stand for supporting work pieces such as pipes.
A tripod-type work stand of the character to which the present invention relates in general is shown, for example, in U.S. Pat. No. 2,831,583 to Wright, et al. This stand comprises a base for supporting a vise, and three legs pivotally attached to the base for displacement between extended and retracted positions relative thereto. In the extended positions the legs are in a tripod configuration for supporting the base above an underlying surface, and in the retracted positions the legs are generally parallel to one another to facilitate storage and transportation of the stand. An assembly of pivotally interconnected plates is stored between the legs when the latter are in the retracted positions and, in the extended positions of the legs, the plate assembly places the legs in the latter position and provides a tray for supporting tools and the like.
Another foldable tripod-type vise stand is available from Sumner Manufacturing Company of Houston, Tex. under the latter company's product designation NLV Tri-Stand Pipe Vise. The latter comprises a pipe vise mounted on a base plate to which three legs are mounted for pivotal displacement between retracted and extended positions. A tubular support extends downwardly from the base between the legs and carries a slidable ring which is pivotally interconnected with the legs by link members such that the ring is slidable upwardly and downwardly along the tubular member to respectively displace the legs from the extended to the retracted position and thence back to the extended position. A carrying handle is attached to the tubular member to facilitate carrying the stand when the legs are in the retracted positions thereof.
While stands of the foregoing character serve their intended purpose, there are a number of concerns with regard to the use of the stands. In this respect, for example, physically displacing the legs of the stand between the extended and retracted positions thereof is difficult and cumbersome and, in the retracted positions of the legs, there is no stability against unintended displacement of the legs toward the extended position if, for example, the stand is inclined in the direction promoting displacement of the legs relative to the base and toward the extended positions thereof. Still further, there is excessive free-play as the result of wear and/or an accumulation of manufacturing tolerances between the legs, base and other parts of the stands mentioned above, and the excessive free-play interferes with a smooth displacement of the legs and transition of the component parts of the stand between the extended and retracted positions of the legs.